Abstract: An embodiment relates to a polymeric composition for a polythiourethane-based optical material, wherein the polymeric composition, comprising a particular additive, may appropriately adjust the reactivity of an isocyanate such that viscosity is maintained low for a predetermined period of time, and thus is capable of preparing a high-quality polythiourethane-based optical material, without a complicated purification process. Moreover, a polythiourethane-based optical material according to an embodiment has not only a uniform refractive index, but also a low yellow index, and thus may be used as a variety of plastic optical lenses, such as an eyeglass lens or a camera lens and the like.

Abstract: The embodiments relate to a process for preparing a polythiol composition, which comprises reacting a halogen compound or an alcohol compound with thiourea to prepare a thiouronium salt solution; and adding a basic solution to the thiouronium salt solution to hydrolyze it. The hydrolysis reaction is terminated when the area of peak A in the graph measured by gel permeation chromatography of the reactant in the hydrolysis step under certain conditions is 0.5% to 8% based on the total peak area. A tetrafunctional polythiol composition having high purity can be obtained. Thus, an optical lens having excellent color, transparency, and refractive index can be obtained.

Abstract: According to one embodiment, in producing polythiols in a manner similar to a conventional method, a polythiol having improved storage stability may be produced in a convenient manner by adjusting reaction conditions so as to prevent thiourea from remaining within products. In particular, the equivalent weight of thiourea to be used in a reaction may be adjusted to a predetermined range, thereby reducing the amount of unreacted thiourea, and thiourea may be removed once more in a sub sequent process, thereby effectively removing remaining thiourea while achieving a high yield. The polythiol thus produced does not contain residual thiourea, and thus does not show discoloration or cloudiness caused by precipitates even under prolonged storage or high-temperature conditions.

Abstract: An embodiment relates to an aromatic polythiol compound for optical materials, and the aromatic polythiol compound according to the embodiment contains a phenyl group and a large number of sulfur atoms in its polythiol structure so that a polymerizable composition and an optical material obtained therefrom have excellent optical properties such as high refractive index and low specific gravity, as well as excellent mechanical properties such as low cure shrinkage; thus, they can be advantageously used for producing various plastic optical lenses such as eyeglass lenses and camera lenses.

Abstract: The embodiments relate to a process for preparing a polythiol composition, which comprises reacting a halogen compound or an alcohol compound with thiourea to prepare a thiouronium salt solution; and adding a basic solution to the thiouronium salt solution to hydrolyze it. The hydrolysis reaction is terminated when the area of peak A in the graph measured by gel permeation chromatography of the reactant in the hydrolysis step under certain conditions is 0.5% to 8% based on the total peak area. A tetrafunctional polythiol composition having high purity can be obtained. Thus, an optical lens having excellent color, transparency, and refractive index can be obtained.

Abstract: According to one embodiment, in producing polythiols in a manner similar to a conventional method, a polythiol having improved storage stability may be produced in a convenient manner by adjusting reaction conditions so as to prevent thiourea from remaining within products. In particular, the equivalent weight of thiourea to be used in a reaction may be adjusted to a predetermined range, thereby reducing the amount of unreacted thiourea, and thiourea may be removed once more in a sub sequent process, thereby effectively removing remaining thiourea while achieving a high yield. The polythiol thus produced does not contain residual thiourea, and thus does not show discoloration or cloudiness caused by precipitates even under prolonged storage or high-temperature conditions.

Abstract: The embodiments relate to a polythiol composition for a plastic optical lens and a polythiourethane-based plastic optical lens prepared therefrom. In the embodiments, a first polythiol compound having an ester group and a mercapto group only as a hydrogen-bondable functional group and a second polythiol compound having an ester group and a hydrogen-bondable functional group other than a mercapto group are used in an appropriate amount. Thus, it is possible to control the viscosity of a polymerizable composition at the initial stage of polymerization at a low temperature of 5 to 15° C. and to stabilize the rate of increase in the viscosity of the composition and the reaction rate thereof, thereby preventing the generation of striae, bubbles, and the like. Further, various plastic lenses such as eyeglass lenses, camera lenses, and the like having excellent appearance characteristics (without striae and bubbles) and excellent optical characteristics can be obtained from the composition.

Abstract: An embodiment relates to a polymeric composition for a polythiourethane-based optical material, wherein the polymeric composition, comprising a particular additive, may appropriately adjust the reactivity of an isocyanate such that viscosity is maintained low for a predetermined period of time, and thus is capable of preparing a high-quality polythiourethane-based optical material, without a complicated purification process. Moreover, a polythiourethane-based optical material according to an embodiment has not only a uniform refractive index, but also a low yellow index, and thus may be used as a variety of plastic optical lenses, such as an eyeglass lens or a camera lens and the like.

Abstract: Provided is a preparation of a thioether-based polythiol in a high purity using a metal monosulfide for the incorporation of a thioether group, wherein the content of such components as a metal polysulfide present in the metal monosulfide is controlled to a predetermined level or lower. As a result, an optical lens of high quality with a high refractive index can be produced using the polythiol.

Abstract: Embodiments relate to a polythiol composition for a plastic optical lens and a polythiourethane-based plastic optical lens prepared therefrom. In the embodiments, a first polythiol compound having mercapto groups only as a hydrogen-bondable functional group and a second polythiol compound having mercapto groups as a hydrogen-bondable functional group and a hydrogen-bondable functional group other than a mercapto group are used in an appropriate amount. Thus, not only is it possible to control the viscosity of a polymerizable composition at the initial stage of polymerization at a low temperature of 5 to 15° C. and to stabilize the rate of increase in the viscosity of the composition and the reaction rate thereof, but also the change in the viscosity at a low temperature is low, thereby preventing the generation of striae, bubbles, and the like.

Abstract: An embodiment relates to an aromatic polythiol compound for optical materials, and the aromatic polythiol compound according to the embodiment contains a phenyl group and a large number of sulfur atoms in its polythiol structure so that a polymerizable composition and an optical material obtained therefrom have excellent optical properties such as high refractive index and low specific gravity, as well as excellent mechanical properties such as low cure shrinkage; thus, they can be advantageously used for producing various plastic optical lenses such as eyeglass lenses and camera lenses.

Abstract: Embodiments relate to a polythiol composition for a plastic optical lens and a polythiourethane-based plastic optical lens prepared therefrom. In the embodiments, a first polythiol compound having mercapto groups only as a hydrogen-bondable functional group and a second polythiol compound having mercapto groups as a hydrogen-bondable functional group and a hydrogen-bondable functional group other than a mercapto group are used in an appropriate amount. Thus, not only is it possible to control the viscosity of a polymerizable composition at the initial stage of polymerization at a low temperature of 5 to 15° C. and to stabilize the rate of increase in the viscosity of the composition and the reaction rate thereof, but also the change in the viscosity at a low temperature is low, thereby preventing the generation of striae, bubbles, and the like.

Abstract: The embodiments relate to a polythiol composition for a plastic optical lens and a polythiourethane-based plastic optical lens prepared therefrom. In the embodiments, a first polythiol compound having an ester group and a mercapto group only as a hydrogen-bondable functional group and a second polythiol compound having an ester group and a hydrogen-bondable functional group other than a mercapto group are used in an appropriate amount. Thus, it is possible to control the viscosity of a polymerizable composition at the initial stage of polymerization at a low temperature of 5 to 15° C. and to stabilize the rate of increase in the viscosity of the composition and the reaction rate thereof, thereby preventing the generation of striae, bubbles, and the like. Further, various plastic lenses such as eyeglass lenses, camera lenses, and the like having excellent appearance characteristics (without striae and bubbles) and excellent optical characteristics can be obtained from the composition.

Abstract: Provided is a preparation of a thioether-based polythiol in a high purity using a metal monosulfide for the incorporation of a thioether group, wherein the content of such components as a metal polysulfide present in the metal monosulfide is controlled to a predetermined level or lower. As a result, an optical lens of high quality with a high refractive index can be produced using the polythiol.

Abstract: Disclosed is to prevent generation of byproducts or a deterioration in the physical properties of a polythiol composition that may be caused by active oxygen during storage thereof by way of controlling the content of active oxygen in the polythiol composition after the synthesis of the polythiol. As a result, it is possible to enhance the long-term storage stability of a polythiol composition after it has been synthesized until it is used in the polymerization reaction.